1. Field of the Invention
The present invention relates to lockable electrical connectors and, more particularly, to a lockable electrical female connector, such as, without limitation, a female receptacle connector for use with extension cords, capable of accommodating therein a male plug having at least two prongs. The locking features of the lockable electrical female connector serve to allow the prongs of the male plug to be quickly and easily locked and unlocked.
2. General Background
As is known, electrical connectors comprise a female receptacle connector and a male plug capable of being received in such female receptacle connector for transferring power, usually from the power contacts of the female receptacle connector to the prongs of the male plug. The male/female connection is maintained by a friction fit between the mated connection of the male plug and the female receptacle connector. Metallic channels of the female receptacle connectors are often stretched because of the repeated insertion and retraction of the prongs of the male plug from such channels. Moreover, prongs of the male plug vary in dimensionality. Therefore, thinner prongs are oftentimes loosely supported within such channels. The loosely supported prongs of the male plug in the female receptacle connector are not sufficiently friction fitted and on occasion become disengaged thereby breaking the flow of electrical power. The user will then reconnect the male plug in the female receptacle connector. This is time consuming and bothersome when a user has a job to perform. This is particularly bothersome on construction sites.
Even if the male/female connection is not broken but the prongs of the male plug recede outwardly from the female receptacle connector, the prongs may become bent or broken or poor or faulty electrical power flow between the metal contacts between the male/female connection may arise. Hazardous conditions exist by the loose electrical contact between the male/female connection wherein arcing or overheating may occur.
Several devices have been patented which are aimed at locking the prongs of the male plug and in the female receptacle connector housing to prevent disengagement of the male plug from the female receptacle connector.
U.S. Pat. No. 4,061,409, by Bealmear, teaches a releasable locking means for preventing the accidental separation of the male plug from the female receptacle connector. A prong of the male plug has a notch formed therein which engages a pin member of a rotatable knob. As the notch is coupled to the pin member, the prong is prevented from accidentally becoming separated from the female receptacle connector.
U.S. Pat. No. 4,530,556, by Bonus, discloses a safety electrical receptacle which is coupled to a conventional wall outlet. The prongs of the male plug are coupled in the wall outlet in a conventional manner via the safety electrical receptacle. The safety electrical receptacle serves to lock the prongs in the safety electrical receptacle thereby the prongs are prevented from being pulled out from the wall outlet. As can be readily seen, the safety electrical receptacle taught by Bonus serves as an adaptor for allowing the prongs of the male plug to be locked to a conventional wall outlet. The safety electrical receptacle taught by Bonus comprises a locking wedge member moved in the vertical plane. A special tool must be used to move the locking wedge in its locking and unlocking positions. As can be appreciated, the invention, by Bonus, does not allow the prongs to be quickly and easily locked and unlocked. Moreover, on occasion such tool has become misplaced thereby the safety electrical receptacle cannot be locked.
The invention, by Bonus, also provides for a ball member to be inserted in the locking wedge member wherein the ball member has coupled thereto a screw means. The ball member tends to wear the interior surfaces of the locking wedge thereby the ball member begins to twist and turn in the locking wedge member. As can be appreciated, as the ball member twists and turns, the locking wedge member eventually cannot be easily moved, if at all, between the locking position and the unlocking position.
Furthermore, the invention, by Bonus, provides for two locking wedges which serve to secure the prongs in the prong-receiving slots when actuated by the movement by the locking wedge member. The locking wedges are not secured to the prong-receiving slots and are susceptible to becoming displaced.
U.S. Pat. No. 4,867,697, by Borges, discloses a self-locking electrical receptacle with a spring-biased wedge for expanding the male plug's prongs within the electrical receptacle. Expanding of the male plug's prongs is problematic in that the prongs become bent and may not be readily inserted in other electrical receptacles.
U.S. Pat. No. 5,551,884, by Burkhart, Sr., teaches a lockable electrical socket which has a pair of grasping jaws which can retain an electrical plug in place. The plug can be released by pushing in the plug and then allowing the plug retaining assembly and the plug to be thrust out under spring pressure. Alternately, the invention, by Burkhart, Sr., discloses the use of a key to thrust out the plug.
Other patents present in the art are U.S. Pat. No. 2,528,121, by Dickinson; U.S. Pat. No. 2,732,531, by Janowiec; and, U.S. Pat. No. 3,891,289, by Hanke; all of which are directed to lockable electrical receptacle connectors for locking therein prongs of male plugs, but do not meet the needs of the lockable electrical female connector of the present invention.